What is Hyperloop?

SpaceX founder Elon Musk made headlines Monday after releasing a 57-page concept design of Hyperloop, a tube-shaped transportation mechanism that, if built, could be "better than flying or driving."

According to Musk, Hyperloop capsules would zip passengers through a tube at 1126 kph, making the trip between Los Angeles and San Francisco in half an hour -- about half the time it takes an airplane.

There's more: Hyperloop is solar-powered, making it better for the environment, and resistant to earthquakes, ice, wind, fog and rain.

"Capsules travel in a carefully controlled and maintained tube," Musk writes. "The propulsion system is integrated into the tube and can only accelerate the capsule to speeds that are safe in each section. With human control error and unpredictable weather removed from the system, very few safety concerns remain."

Capsules would float through tubes at 1,126 kph

So what is Hyperloop, anyway?

Musk describes Hyperloop as a tube that's built over, or under, the ground. Pods containing passengers would float through a tube from stop to stop, propelled by powerful fan at the front of the pod that expels air out the rear.

A passenger-only version of the train would cost an estimated $6 billion US to build, while a version that could transport vehicles and passengers could cost as much as $7.5 billion.

Solar panels on top of the tube would keep the pod moving.

"Transporting 7.4 million people each way and amortizing the cost of $6 billion over 20 years gives a ticket price of $20 for a one-way trip for the passenger version of Hyperloop," Musk writes.

The document was released without patents in an open-source format. Musk is inviting scientists to make improvements to the design.

Critics are calling the concept a "pipe dream," - pun intended. So far, no investors have stepped up to fund the project.